Currently available display systems include cathode ray tubes and a variety of flat panel displays such as LED arrays, liquid crystal arrays, thin film electroluminescent displays, and gas discharge displays. The flat panel display systems incorporate an X-Y grid of contacts to address and drive the individual display pixels.
Cathode ray tubes are bulky, relatively heavy, and susceptible to image distortion caused by magnetic field variations. For large area displays, the bulk and weight of cathode ray tubes increases rapidly, resulting in the use of projection systems for most large television systems. For flat panel displays, the large number of drivers and addressing lines becomes a limitation for large display sizes. As a result of these limitations, there is a need for a display system that combines the low volumes of flat panel displays with the relatively simple scanning techniques of cathode ray tubes.
Several efforts have been under way to provide such an enhanced system that would be particularly suitable for large displays. One approach has been the reformatting of the cathode ray tube envelope and electron gun geometry. This approach is a variation of the standard cathode ray tube electromagnetic or electrostatic deflection scheme, and seeks to direct the electron beam or beams within the confines of a less bulky vacuum envelope. The need to direct the electron beam within the vacuum envelope, however, requires that the envelope be sufficiently massive or contain sufficient internal supports to withstand the high force generated by atmospheric pressure over large areas. A second approach has been a reduction in the number of drivers required in a flat panel display system. This approach eliminates the need for a scanned beam, but may still require internal supports, particulary for the gas discharge displays and liquid crystal displays.